<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <script src="jquery1.8/jquery-1.8.0.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $("#myFile").change(function () {
                var filepath = $("input[name='myFile']").val();
                var extStart = filepath.lastIndexOf(".");
                var ext = filepath.substring(extStart, filepath.length).toUpperCase();
                if (ext != ".BMP" && ext != ".PNG" && ext != ".GIF" && ext != ".JPG" && ext != ".JPEG") {
                    alert("图片限于bmp,png,gif,jpeg,jpg格式");
                    $("#fileType").text("")
                    $("#fileSize").text("");
                    return false;
                } else { $("#fileType").text(ext) }
                var file_size = 0;
                if ($.browser.msie) {
                    var img = new Image();
                    img.src = filepath;
                    while (true) {
                        if (img.fileSize > 0) {
                            if (img.fileSize > 3 * 1024 * 1024) {
                                alert("图片不大于100MB。");
                            } else {
                                var num03 = img.fileSize / 1024;
                                num04 = num03.toFixed(2)
                                $("#fileSize").text(num04 + "KB");
                            }
                            break;
                        }
                    }
                } else {
                    file_size = this.files[0].size;
                    var size = file_size / 1024;
                    if (size > 10240) {
                        alert("上传的图片大小不能超过10M！");
                    } else {
                        var num01 = file_size / 1024;
                        num02 = num01.toFixed(2);
                        $("#fileSize").text(num02 + " KB");
                    }
                }
                return true;
            });
        });
    </script>
    <title>无标题文档</title>
</head>
<body>
    <table width="500" cellspacing="0" cellpadding="0">
        <tr>
            <td width="72" id="fileType">
            </td>
            <td width="242">
                <input type="file" name="myFile" id="myFile" />
            </td>
            <td width="184" id="fileSize" class="fileSize">
            </td>
        </tr>
    </table>
</body>
</html>